swift-protocols

问题 I'm trying to do something like that, but then, ParentC doesn't conform to Parent because its children member isn't Child but ChildC Which is weird because ChildC implements Child ... Is this a limit of Swift? Or is there is a way of doing that? (I do not ask for an alternative solution, I want to know if this is possible) protocol Parent: Codable { var children: [Child] { get } } protocol Child: Codable { var name: String { get } } struct ParentC: Parent { var children: [ChildC] } struct

问题 I'm trying to write a protocol that reconciles two different structs that describe the same concept, a stop of some kind. Both have a Code , Description , and Latitude & Longitude coordinates, but for one type, the Description could be nil , and for the other type, the coordinates might be nil . How can I write a single protocol that reconciles these two structs? Here's my protocol: protocol Stop { var Code : String { get } var Description : String { get } var Latitude : Double { get } var

问题 I tried to create protocol which can be only implemented by classes which inherit from UIView , what was my surprise when this code compiles without errors (in Swift 3.0): protocol TestsProtocol { func test() } extension TestsProtocol where Self: UIView { } class FooClass: TestsProtocol { func test() { } } We can see that FooClass don't inherit from UIView , using protocol extension I wan't to force that only classes which inherit from UIView can implement it. As far as I remember this would

问题 I tried to create protocol which can be only implemented by classes which inherit from UIView , what was my surprise when this code compiles without errors (in Swift 3.0): protocol TestsProtocol { func test() } extension TestsProtocol where Self: UIView { } class FooClass: TestsProtocol { func test() { } } We can see that FooClass don't inherit from UIView , using protocol extension I wan't to force that only classes which inherit from UIView can implement it. As far as I remember this would

问题 I'm implementing a model: It has structs ClientSummary and ClientDetails ClientDetails struct has all properties of ClientSummary struct + some extra properties Both structs have main initializer init(jsonDictionary: [String: Any]) inits of ClientSummary and ClientDetails share big part of the code There is an extension which will work with shared functionality of those structs. The most straightforward solution which came to my mind is just classic inheritance, but it doesn't work for value

问题 I'd like to have a generic weak reference to an object and parametrize it by a protocol that is class-bound. Here is the code example that does not work in my case: protocol Protocol: class { // also written as `protocol Protocol: AnyObject {` func function() } final class A: Protocol { func function() {} } final class Weak<Type> where Type: AnyObject { final private weak var property: Type? init(property: Type) { self.property = property } } let a = A() let something = Weak<Protocol>

问题 I'd like to have a generic weak reference to an object and parametrize it by a protocol that is class-bound. Here is the code example that does not work in my case: protocol Protocol: class { // also written as `protocol Protocol: AnyObject {` func function() } final class A: Protocol { func function() {} } final class Weak<Type> where Type: AnyObject { final private weak var property: Type? init(property: Type) { self.property = property } } let a = A() let something = Weak<Protocol>

问题 I have a Objective C class that has methods that look like this: @class Client; @protocol ClientDelegate <NSObject> @optional -(void) receivedMessageFromClient : (id) message; @end @interface Client : NSObject +(id) setup; @property(nonatomic, strong) id <ClientDelegate> clientDelegate; // more method declarations below I am implementing the ClientDelegate in my Swift class like this: class HomeViewController: UIViewController, ClientDelegate { var client : AnyObject? var delegate:

来源： https://stackoverflow.com/questions/57282655/why-there-cannot-be-more-than-one-conformance-even-with-different-conditional

来源： https://stackoverflow.com/questions/57282655/why-there-cannot-be-more-than-one-conformance-even-with-different-conditional